Changeset 40abf56 in mainline for uspace/lib/c/generic/fibril.c

Timestamp:

2018-07-18T19:42:28Z (6 years ago)

Author:

Jiří Zárevúcky <jiri.zarevucky@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

9bde0d5

Parents:

0b05082

git-author:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-07-18 19:05:08)

git-committer:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-07-18 19:42:28)

Message:

Make sure that a thread with uninitialized TLS does not need to call malloc()
to initialize it.

For threads and tasks created by loader, we create TLS beforehand and pass
it to the child. For tasks spawned directly by the kernel, we require it is
a static executable and allocate the initial TLS using as_area_create() instead
of the libc allocator.

File:

• uspace/lib/c/generic/fibril.c (modified) (7 diffs)

uspace/lib/c/generic/fibril.c

@@ -50 +50 @@
 #include "private/thread.h"
 #include "private/fibril.h"
-
+#include "private/libc.h"
 
 /**
@@ -85 +85 @@
 }
 
-/** Setup fibril information into TCB structure
- *
- */
-fibril_t *fibril_setup(void)
-{
-        tcb_t *tcb = tls_make();
+/** Allocate a fibril structure and TCB, but don't do anything else with it. */
+fibril_t *fibril_alloc(void)
+{
+        tcb_t *tcb = tls_make(__progsymbols.elfstart);
         if (!tcb)
                 return NULL;
@@ -102 +100 @@
         tcb->fibril_data = fibril;
         fibril->tcb = tcb;
-
-        /*
-         * We are called before __tcb_set(), so we need to use
-         * futex_down/up() instead of futex_lock/unlock() that
-         * may attempt to access TLS.
-         */
-        futex_down(&fibril_futex);
-        list_append(&fibril->all_link, &fibril_list);
-        futex_up(&fibril_futex);
-
+        fibril->is_freeable = true;
+
+        fibril_setup(fibril);
         return fibril;
+}
+
+/**
+ * Put the fibril into fibril_list.
+ */
+void fibril_setup(fibril_t *f)
+{
+        futex_lock(&fibril_futex);
+        list_append(&f->all_link, &fibril_list);
+        futex_unlock(&fibril_futex);
 }
 
@@ -122 +123 @@
         if (!locked)
                 futex_unlock(&fibril_futex);
-        tls_free(fibril->tcb);
-        free(fibril);
+
+        if (fibril->is_freeable) {
+                tls_free(fibril->tcb);
+                free(fibril);
+        }
 }
 
@@ -239 +243 @@
         fibril_t *fibril;
 
-        fibril = fibril_setup();
+        fibril = fibril_alloc();
         if (fibril == NULL)
                 return 0;
@@ -248 +252 @@
             AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE | AS_AREA_GUARD |
             AS_AREA_LATE_RESERVE, AS_AREA_UNPAGED);
-        if (fibril->stack == (void *) -1) {
+        if (fibril->stack == AS_MAP_FAILED) {
                 fibril_teardown(fibril, false);
                 return 0;
@@ -324 +328 @@
 fibril_t *fibril_self(void)
 {
-        return __tcb_get()->fibril_data;
+        assert(__tcb_is_set());
+        tcb_t *tcb = __tcb_get();
+        assert(tcb->fibril_data);
+        return tcb->fibril_data;
 }